Thursday, November 10, 2016

Two Gel Cells and a Heatsink: BITX40 Power Hack

I blame Pete Juliano N6QW for this.  And Farhan.  Pete has been leading us astray with his talk of high power linear amplifiers ("Two 813s kid, that's all you need!").  And Farhan practically pushed us beyond QRP limits by placing a separate DC power connector for the IRF510 final amplifier on his new BITX 40 Module board.  Farhan writes: 

There are jump-points from where you can add more modules like the DDS, more bands, better audio amplifier, etc. Imagination is your limit. You can separately increase the power amplifier's supply voltage to 25 volts to be more than 20 watts of power : You will have to add a better heat sink. The mods are on the way! (from

A while back Chris KD4PBJ sent me some very nice heat sinks -- one of those would fit quite nicely on the PA side of the BITX40 board.  And I just happen to have two 12V Gel cell batteries. One will power the board and the two together will power the IRF510.  With 20 watts out to my dipole I feel confident that I will WIN the upcoming ARRL Phone Sweepstakes (in my category: Homebrew VFO, Northern Virginia).

73 from Northern Virginia  Bill N2CQR


  1. Oh, yeah, he's just ASKIN' for us to go QRO with it.
    Got mine this week, and I'm at 'Receive'. It was... MISSING the D9 / VFO Varactor Diode! Must've fallen off between 'test' and 'box'.
    Although, I'm planning to just use DDS, it is fun to play with the VFO.

  2. I just received my BITX40 this week. Have you tried out "More Power?" Did you have any luck? 73, KF5GLB

  3. Bill Please share the details on what you did... With pictures / diagram